Radiation Shape Factors for Channels With Varying Cross Sections

1988 ◽  
Vol 110 (1) ◽  
pp. 264-266 ◽  
Author(s):  
T. L. Eddy ◽  
G. E. Nielsson
Keyword(s):  
Cross Sections ◽  
Shape Factors

Allowable Stresses for Nonrectangular Sections Under Combined Axial and Bending Loads

1988 ◽  
Vol 110 (2) ◽  
pp. 188-193
Author(s):  
S. Chattopadhyay
Keyword(s):  
Cross Sections ◽  
Rectangular Cross Section ◽  
Shape Factors ◽  
Division 1 ◽  
Asme Code ◽  
Depth Study ◽  
Section Viii ◽  
Bending Loads ◽  
Interaction Curves ◽  
Division 2

The design stress allowables for various loading conditions involving bending in Section III, Division 1 and Section VIII, Division 2 of the ASME Boiler and Pressure Vessel Code are based on the assumption of a rectangular cross section of the structural members. These allowables do not necessarily provide the same level of safety for all general cross sections. In this work, stress allowables have been proposed for design, level C and test condition loadings to provide adequate safety for all combinations of axial and bending loads. The limits are based on an in-depth study of the interaction curves for the fully plastic condition under combined axial and bending loads. These proposed limits are intended to replace the existing ones in the ASME Code. These modifications apply to the design, level C and testing limits. (NB-3221.3, NB-3224 and NB-3226) of Section III, Division 1, and to the Design and Testing limits (AD-140 and AD-151) of Section VIII, Division 2 of the ASME Code. The modified limits are based on the inclusion of shape factors of individual cross sections.

Poiseuille-Number-Based Kozeny–Carman Model for Computation of Pore Shape Factors on Arbitrary Cross Sections

2021 ◽  
Author(s):  
Valdecir A. Santos Júnior ◽  
Antônio F. Silva Júnior ◽  
Tatiana A. Simões ◽  
Gustavo P. Oliveira
Keyword(s):  
Cross Sections ◽  
Pore Shape ◽  
Shape Factors ◽  
Poiseuille Number

scholarly journals Shear-induced microstructures and dynamics processes of phospholipid cylinders in solutions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yue Shan ◽  
Xiaowei Qiang ◽  
Jianzhu Ye ◽  
Xianghong Wang ◽  
Linli He ◽  
...  
Keyword(s):  
Shear Rate ◽  
Shear Flow ◽  
Cross Sections ◽  
Polymer Chains ◽  
Dynamic Processes ◽  
Radius Of Gyration ◽  
Particle Dynamic ◽  
Shear Direction ◽  
Shape Factors ◽  
Strong Shear

Abstract Shear-induced microstructures and their corresponding dynamic processes are investigated for phospholipid cylinders in aqueous solution by dissipative particle dynamic simulation. Various phospholipid cylinders with cross-sections, which are formed under shear-free flow, are selected to examine the effects of shear flow on their structures and dynamic processes. Shear flow induces the transition from cylinders into vesicles at weak rate and the transition into vesicle–lamella mixtures with increased shear rate and lamella structures at the strong shear rate. Then, the average radius of gyration and shape factors of the polymer chains in the dynamic processes are discussed in detail. Results show that shear flow causes the structure of the polymer chains to be elongated along the shear direction, and the configuration of the polymer chain can be rapidly transformed into an ellipsoid structure under strong shear.

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

Surface ultrastructure of danazol treated rat endometrium: A SEM study

1983 ◽  
Vol 41 ◽  
pp. 556-557
Author(s):  
R.P. Apkarian ◽  
J.S. Sanfilippo
Keyword(s):  
Cross Sections ◽  
Reproductive Tract ◽  
Preliminary Investigation ◽  
Breast Disease ◽  
Distal Segment ◽  
Uterine Horn ◽  
Female Reproductive Tract ◽  
Ultrastructural Changes ◽  
Cycle Phase ◽  
Sprague Dawley

The synthetic androgen danazol, is an isoxazol derivative of ethisterone. It is utilized in the treatment of endometriosis, fibrocystic breast disease, and has a potential use as a contraceptive. A study was designed to evaluate the ultrastructural changes associated with danazol therapy in a rat model. The preliminary investigation of the distal segment of the rat uterine horn was undertaken as part of a larger study intended to elucidate the effects of danazol on the female reproductive tract.Cross-sections (2-3 mm in length) of the distal segment of the uterine horn from sixteen Sprague-Dawley rats were prepared for SEM. Ten rats in estrus served as controls and six danazol treated rats were noted to have alterations of the estrus cycle i.e. a lag in cycle phase or noncycling patterns. Specimens were fixed in 3% glutaraldehyde in 0.05M phosphate buffer containing CaCl2 at pH 7.0-7.4 and chilled to 4°C. After a brief wash in distilled water, specimens were passed through a graded series of ethanol, critical point dryed in CO2 from absolute ethanol, and coated with 6nm Au. Observations were made with an IS1-40 SEM operated at 15kV.

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